Glow discharge polymerization among such reactive functional silances as 3-methacryloxypropyltrimethoxysilane (MSL), 3-glycidoxypropyltrimethoxysilane (ESL), and vinyltrimethoxysilane (VSL) on poly(methyl methacrylate) was investigated by means of Fourier transform infrared spectroscopy, ESCA analysis, and contact angle measurement. Flow rate of monomer influenced both polymer deposition rate and polymer elemental composition. Infrared spectra showed differences in chemical structure among the polymers prepared from the different silanes. All of the polymers obtained contained similar chemical groups such as CH3, CH2, SiOSi, and SiOC. Polymers deposited from MSL and ESL contained highly hydrophilic functional groups like COH, SiOH, and CO on the uppermost layer while that from VSL contained highly hydrophobic functional groups like CH3 groups. Chemical analysis by ESCA and contact angle measurement gave evidence for the similarity of the polymers prepared from MSL and ESL, in contrast with the differences of the polymers prepared from VSL.